Lubricant



Patented Aug. 20, 1940 UNITED STATES v LUBRICANT Waldersee B. Hendrey, Beacon, N. Y., assignor to The Texas Company, New York, N. Y., a cor poration of Delaware No Drawing. Application April 1, 1937, Serial No. 134,275

6 Claims.

This invention relates to lubricants and has to do particularly with improvements in lubricating oil compositions intended for the lubrication of automotive engines, especially under severe conditions, wherein bearing corrosion, cylinder and piston ring wear may be encountered.

The invention contemplates the addition to lubricating compositions of certain materials which are specific for pvercoming the above mentioned difiiculties and for generally improving the lubricant.

The addition of fatty oils, such as lard oil, sperm oil, tallow, etc., to mineral lubricating oils, increases the oiliness of the compounded oil and reduces cylinder wear. The addition of such oils, however, does not substantially reduce the piston ring sticking and bearing corrosion.

It has been found that the use of a complex glyceride phosphoric acid ester, such as lecithin and cephalin, in combination with a fatty oil, will reduce cylinder wear and alsoimprove the ring sticking and bearing corrosion properties.

The following example will illustrate the invention although the invention is not limited to the specific example.

To a sample of commercial airplane oil was added, 3% by weight of sperm oil and 0.2% by weight of soybean lecithin. The tests on the compounded oil, as compared with the airplane base oil, are as follows:

Base compounded oil oil Saybolt universal viscosity at 210 F 124 116 Ring sticking time (percent better than reference oil) l7 75 Bearing corrosion, lead index ll 32 The ring sticking time was determined on a Cooperative Fuel Research, single cylinder, fixed compression engine running at 900 R. P. M. operated at a jacket temperature of 375 F., throttle wide open and with mixture ratio adjusted for maximum power. At six hour intervals the cylinderwas removed and piston examined for sticking piston rings. If none were found, the test was continued but if any were found to be stuck. the engine was cleaned and the test rerun with a fresh supply of the same oil. This time, however, the test was run continuously for a period of three hours less than that found previously necessary to stick the rings. Since the ring sticking time for any given oil will vary considrably with engine condition, it is necessary to run a reference oil preceding and following each oil rated. Then the ring sticking quallty of an oil is rated as the per cent increase or decrease of the time required for it to stick rings for comparison with the reference 011. The reference oil was a commercial airplane oil of ap- 5 proximately 120 Sayboltviscosity at 210 F.

The lead index" is determined by exposing a given quantity of oil to controlled oxidizing conditions. The inherent and unstable catalysis of the metal surfaces exposed to the test oil during 10 the test are minimized by the application of a chemically inactive coating. Measured amounts of an active and controllable oxidation promoter such as lead naphthenate are added during repeatedtests until the maximum amount which can be added without causing any corrosion to a cadmium-silver alloy test bearing is determined. The lead index of the test oil is defined as one thousand times this amount and is interpreted to be a measure of the test oils ability to undergo oxidation without the development of acids which are corrosive to cadmium-silver bearings.

The amounts of the fatty oil and phosphatid are not limited to thosegiven in the specific example. A considerable range of percentages of 25 the materials may be used, depending on the oil and results desired. In general, about 1-5% of fatty oil will be suflicient and preferably around 2-3%. The amount of phosphatide generally ranges from about .1-1%, preferably around 30 .2-.5%.

While the invention is useful in connection with the preparation of airplane oils which are used in engines operating at high cylinder temperatures, it is contemplated within the scope of 35 the invention to use these materials in various types of lubricants, such as lubricating oils ranging from light motor oils to heavycylinder stocks, compounded lubricating oils, greases, etc.

Obviously many modifications and variations of 40 mineral lubricating oil containing about 0.1-1%

of a pho'sphatide and 1-5% of a fatty oil.

2. A mineral lubricating oil containing about 0.2% lecithin and about 3% sperm oil.

3. The method of lubricating the bearings and cylinders of an internal combustion engine which comprises supplying to the bearings and cylinders of said engine a mineral lubricating oil within the motor oil viscosity range containing about (Ll-1.0% of a, phosphatide and about 1-5% of a fatty oil.

4. The method according to claim 3 in which the phosphatide is lecithin and the fatty oil is sperm oil.

5. A lubricating oil adapted for the lubrication of the cylinders and bearings of an internal combustion engine comprising a mineral lubricating 011 within the motor oil viscosity range containing about 0.1-1.0% of a phosphatide and about 1-5% of a fatty oil.

6. A lubricating oil according to claim 5 in 5 which the fatty oil is sperm oil.

WALDERSEE B. HENDREY. 

